I used to have a 200mm lens I don't recall what make because it was stolen along with a camera I used to love a few years ago. But the photos I took with that lens were among the sharpest I have ever taken. I would reccommend a fixed length lens over a zoom lens in terms of overall image any day. Despite the convenience a zoom lens offers. Now I have two cameras and the next lens I buy will be a 200mm or 400mm lens. Or both if I can afford it!

Back in the day, I had a Tokina 90mm f/2.5 macro for a Nikon. That was my favorite back then. The quality was outstanding, both optically, and build-wise. It had the weight which lent to the whole experience too.

The one I use the most is the 17-55 f2.8 Nikkor zoom (back row right in the image below.) I wouldn't say it is my favorite but, since I use it the most, it probably deserves top billing. My emotional favorite is my 45mm f2.8 N Mamiya Sekor wide angle lens for my medium format system. It is so crisp and sharp it makes me smile.

Here are the lenses I use with my Nikon digital SLR's. I don't think there is a bad one in the group, personally. Traveler, note the liberal application of UV filters.

Your comment about an f2.8 lens stopped down to f4 being sharper than an f4 lens wide open can be true indeed. It would certainly be true if the lenses shared the same design, complement of elements and build quality. It is risky to make generalizations, though, because there is a wide variety of designs and quality of construction among photographic lenses.

For very long it was a 50mm f1.4 (M42 screw mount) probably because it was the only one I had . It still is my favourite lens for 35mm. For MF: Bronica S 50mm f3.5 as it is well suited to landscape pictures.